Typical Mining Area Research Articles

Assessing the Risk of Total and Available Potentially Toxic Elements in Agricultural Soil in Typical Mining Areas in Xiangjiang River Basin, Hunan Province

In this study, soil and rice samples from 85 sites in six cities in Hunan Province were analyzed for Cu, Zn, Pb, Cd, Hg, Mn, and Co (total and bioavailable concentrations for soil) in July 2014. The results indicated that the total concentrations of Cu, Zn, Pb, Cd, and Hg in soil had increased significantly compared with the 1980s, and were correlated with their bioavailable concentrations in soil positively. The total concentrations of Cd and Co in soil were correlated with those in rice. Bioavailable concentrations of Cd, Mn, Co, Pb, and Cu represented 64.4%, 33.2%, 12.0%, 11.6%, and 6.1% of the total soil concentrations, respectively. The bioavailable concentrations of Cd and Co in soil had a extremely significant (p < 0.01) positive correlation with those in rice, suggesting that bioavailable concentrations was a better indicator for soil potentially toxic elements contamination. The pH values had a significant influence on the bioavailability of Cd and Cu and the amounts taken up by rice. The Cd contamination in 27.0% rice samples exceeded World Health Organization recommended thresholds. The results added basic pollution distribution data, further revealing the relationships of metals in soil and crops and would offer great help to the metallic pollution control in these areas.

Research on remote sensing prospecting technology based on multi-source data fusion in deep-cutting areas

Tectonically deep-cut areas are difficult to access due to the treacherous terrain, making it difficult to carry out fieldwork in these areas for geological prospecting. Liwu Copper-Zinc Mine is a medium-sized rich polymetallic deposit belonging to deep-cutting areas in tectonic structures. Complicated structures influence the ore development and formation in the region. With the introduction of remote sensing technology, geologic features and mineralisation abnormality information can be recognised effectively in such regions. This can provide scientific references for dividing potential metallogenic regions. Remote sensing images with sub-meter spatial resolutions were collected using the Worldview-2(WV-2) satellite to interpret mineralisation-related geologic bodies and analyse the distribution relationships of mineralisation-controlling structures. Multispectral near-infrared spectral information was acquired through the Landsat-8. Meanwhile, the alteration information of two hydrothermal solutions in the study area related to hydroxide radicals and iron staining was extracted via principal component analysis (PCA) based on Crosta technology. The alteration-related standard spectral information and the measured spectral information of known copper outcrops in the region were collected as guiding spectra. A comparative analysis between guiding spectra and GF-5 graphic information was conducted. Possible mineralisation information distributions in the study area were collected via a spectral angle mapper (SAM) and support vector machine (SVM). The results showed that the WV-2 images were able to accurately identify the mineralised geological bodies. The overall classification precisions of SAM- and SVM-based erratic rock mapping were 80.18% and 83.51%, respectively. The information on the hydroxyl iron staining anomaly had been well fitted to the actual alteration zone by field investigation. An analogy analysis between the multivariate remote sensing prospecting information collected by the above means and the existing typical mining areas in Liwu Region was conducted; the dense areas of mineral control structures and remote sensing anomalies were well integrated. The remote sensing metallogenic prediction model of the region was constructed on this basis. Meanwhile, the potential mineralisation was delineated at target zone 1. In conclusion, the presented technology is based on remote sensing data and the fusion of multi-resolutions. It can provide guidance and references for exploring potential metallogenic regions in deep-cutting areas, especially in fold-development regions.

Mercury horizontal spatial distribution in paddy field and accumulation of mercury in rice as well as their influencing factors in a typical mining area of Tongren City, Guizhou, China.

To make up for the deficiency of the distribution characteristics of mercury (Hg) pollution in soil and rice in a specific area, the relationship between more than ten soil indices and Hg in soil-rice system was analysed, and the main factors affecting mercury accumulation in rice were screened out. So as to provide reliable theoretical and scientific basis for the regulation and safe utilization of Hg-contaminated soil. The Hg-polluted area of Siqian Dam, with a paddy field area of 1.34million square meters, was selected as the research unit. Soil and corresponding rice samples were collected and analysed. Then, common Kriging interpolation was used to explore the spatial distribution differences of mercury content between soil and rice, Pearson correlation analysis and stepwise linear regression were used to analyse the relationship between mercury content and 14 soil indices. In the study area, the total mercury(THg) content in soil and rice was as high as 30.60mg/kg and 160.19µg/kg, respectively, and the methyl mercury(MeHg) content was as high as 14.56µg/kg and 40.32µg/kg, respectively, indicating that mercury pollution in soil and rice was serious. The horizontal spatial distribution of soil THg and MeHg was different. Flood with its sediment and topography were the main reasons for the uneven distribution of Hg content in the region. The spatial distribution of Hg was different between rice and soil. There was no significant correlation between rice and soil THg, but there was a significant correlation between rice and soil MeHg content. Among the 14 soil indices, available potassium was a vital index affecting the accumulation of Hg in rice, followed by pH, Zn, Mn and Fe. The results showed that in weakly acidic and fertile soil, the appropriate reduction of soil pH, OM and available Se and Cr contents could inhibit soil Hg methylation, the reduction of potassium fertilizer application could further reduce rice Hg accumulation. The online version contains supplementary material available at 10.1007/s40201-021-00711-z.

Groundwater pollution and human health risk based on Monte Carlo simulation in a typical mining area in Northern Anhui Province, China

The main objective of this study was to evaluate eight kinds of trace element pollutants in groundwater from a typical coal mine area, and carry out a corresponding health risk assessment for the local populace. To do this, 34 shallow groundwater (SG) samples and 18 mid-layer groundwater (MG) samples were collected from the Sulin mining area. To minimize the uncertainties in the health risk assessment, this paper relied on Monte Carlo simulations and sensitivity analysis. The results revealed that Sr and Mn contents exceeded their corresponding WHO (Guidelines for drinking water quality, 4th edn. Geneva, 2011) guidelines and Chinese groundwater standards (GB/T14848–2017), while the other analyzed trace elements remain below those threshold values. The calculated hazard quotient and hazard index values for adults from ingestion exposure to SG and MG were well below the threshold limit of 1. Probabilistic simulations further show that the total cancer risk value above the limit of 1 × 10−6 is 0% for SG and 29.39% for MG. Sensitivity analysis identified the Sr and Cr contents as the most relevant element variables affecting the probabilistic non-carcinogenic and carcinogenic risk values in the model, respectively.

Experimental Investigation of the Basic Characteristics and Wettability of Oil Shale Dust.

To investigate the influence of basic characteristics of oil shale dust on wet dust removal, oil shales (Longkou oil shales Y1, Y2S2, and Y2S1 and Fushun oil shale) with different oil contents, brown coal (M1), and bituminous coal (M) were selected from a typical mining area in China to test their physiochemical parameters. Their proximate component, chemical structures, surface morphology, and mineral contents were determined. The sedimentation experiments of oil shale dust and coal dust were implemented using three anionic surfactants (AOS, SDS, and SDBS) and a nonionic surfactant (AEO-9), and the wettability of oil shale dust was analyzed and compared with that of coal dust. The experimental results indicate that the moisture content, volatile content, fixed carbon content, and content of oxygen-containing functional groups of oil shale are higher than those of the coal sample; otherwise, contents of ash, SiO2, aliphatic hydrocarbon, and aromatic hydrocarbon are lower. It can be found that oil shale has semiclosed pores, poor connectivity, a small pore size, a large specific surface area, and a rougher surface, which will lead to poorer wettability of oil shale. The wettability of oil shale can be improved by adding surfactants but is still weaker than that of the coal samples. Anionic surfactants are better than nonionic surfactants in improving the wetting performance. Among them, AOS shows strong wetting ability to oil shale dust. The research results of this paper have an important practical significance for analyzing the wettability of oil shale and controlling oil shale dust.

Toxic response of the freshwater green algae Chlorella pyrenoidosa to combined effect of flotation reagent butyl xanthate and nickel

Butyl Xanthate (BX) is a typical flotation reagent used to extract non-ferrous nickel ores, discharged into the surrounding environment of mining areas in large quantities. However, few studies have focused on the toxicity of combined pollution of BX and nickel (Ni) on aquatic plants, especially phytoplankton, the main producer of aquatic ecosystems. The toxicity and potential mechanism of single and combined pollution of BX and Ni at different concentrations (0–20 mg L−1) on typical freshwater algae (Chlorella pyrenoidosa) were studied. BX slightly stimulated the growth of C. pyrenoidosa on the first day, but Ni and Ni/BX mixture significantly inhibited it during incubation. Results showed that the inhibition rate (I) of the pollutants on the growth of C. pyrenoidosa followed the order: Ni/BX mixture > Ni > BX. The 96-h 20% effective inhibitory concentrations (96h-EC20) of Ni and BX on C. pyrenoidosa growth were 3.86 mg L−1 and 19.25 mg L−1, respectively, indicating C. pyrenoidosa was sensitive to pollutants. The content of total soluble protein (TSP) and chlorophyll a (Chl-a) changed significantly, which may be caused by the damage of pollutants to cell structures (cell membranes and chloroplasts). In addition, the I of pollutants on C. pyrenoidosa growth was related to dose, superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA). The increasement of reactive oxygen species (ROS), antioxidant enzymes (SOD and CAT), and MDA content, suggested C. pyrenoidosa suffered from oxidative stress, leading to lipid oxidation. These results will help to understand the toxicity mechanism of pollutants in typical mining areas and assess the environmental risks of pollutants to primary producers in aquatic ecosystems.

Fraction distribution of heavy metals and its relationship with iron in polluted farmland soils around distinct mining areas

Polluted farmland soils around mining areas are usually enriched in Fe (oxyhydr)oxides and various heavy metals (HMs), however, their interactions, essential to evaluate the mobility and availability of HMs, in such soils are poorly understood. In this study, HMs polluted farmland soils were collected from several typical mining areas distributed from the south to the center of China, with distinct soil physicochemical properties. We comparatively analyzed the chemical fractions of HMs and Fe in these soils and determined the association relationship between HMs and Fe fractions using chemical extraction and correlation analysis. Most soils contain multiple HMs like As, Cu, Pb, Zn, and Cd, with varying environmental risks across the regions. Excluding the residual fraction, Cu, Pb, and Cd mainly exist in the reducible fraction, while Zn predominately accumulates in the oxidizable fraction. The total Cu, Pb, and Zn exhibit positive correlations with their available contents (P < 0.01), suggesting that the availability of these HMs is predictable by their total contents. Additionally, the positive correlations among Pb, Zn and Cd indicate that these HMs are associated with each other. Arsenic in these soils is predominantly associated with various Fe fractions, while Cd shows a closer relationship with crystalline Fe oxides and probably locates in the mineral structure. Additionally, As and Cd exhibit significant positive correlations within various Fe oxides, suggesting a synergistic accumulation effect in these soils. These new insights into the fraction distribution of HMs and their association properties with Fe fractions are essential to ecological risk assessment and remediation of HMs in polluted farmland soils.

Level, Source, and Spatial Distribution of Potentially Toxic Elements in Agricultural Soil of Typical Mining Areas in Xiangjiang River Basin, Hunan Province.

The concentrations, chemical availability, distribution, and sources of potentially toxic elements (PTEs) in the soil of Xiangjiang Basin in Hunan Province, China were investigated at 85 sites. The highest mean concentrations of Cd, Cu, Zn, As, and Pb were observed in Hengyang, whereas those for Mn, Co, and Hg were observed in Changde. The pollution index values followed the order: Cd > Hg > Cu > Zn > As > Pb; the mean geo-accumulation index values were in the order: Cd > Hg > Pb > Cu > Zn > As > Co > Mn. Cd was associated with moderate contaminated level, Hg and Pb were associated with moderate contaminated to uncontaminated level, and Cu, Zn, As, Co, and Mn were associated with uncontaminated level of pollution. Furthermore, 64.5% of Cd was water-soluble and exhibited exchangeable fractions; its chemical availability posed a risk to the ecosystem. Spatial analysis, principal component analysis, and a positive matrix factorization model were used to assess the PTE sources. Four principal components contributed to 88.8% of the 8 PTEs concentrations. Mining, smelting, industrial, and agricultural activities, alongside sewage irrigation, the use of agrochemicals, and vehicular emissions are the possible anthropogenic sources that pollute agricultural products and threaten human health in the Xiangjiang Basin.

Experimental evaluation of physical, mechanical, and permeability parameters of key aquiclude strata in a typical mining area of China

Coal production safety and protection of water resources in coal mines located under aquifers requires an in-depth analysis of key aquiclude strata (KAS), including their physical, mechanical, and seepage characteristics. Based on hydrogeological conditions of thickness and buried depth of coal seam, thickness and water abundance of the aquifer, KAS thickness, etc., the experimental comprehensive testing method of mechanical and permeability parameters of KAS in the Wugou Coal Mine, China, are proposed. This paper applies state-of-the-art X-ray diffraction (XRD), scanning electron microscopy (SEM), and mechanical test methods to study mineral composition, microstructure, mechanical properties, water absorption, and softening coefficient of KAS rock samples collected from the mine under study. The comprehensive analysis of the results obtained made it possible to clarify the particular water-inrush mechanism and stability control of KAS using the revealed stress-strain-permeability dependencies of composite KAS and non-Darcy seepage behavior of post-peak fractured KAS. The model of KAS damage status with different backfill effects is established and successfully applied to the case study. Findings of this study are considered instrumental in the KAS-based prevention of water-inrush hazards and more rational exploitation of coal resources.

典型矿区植被覆盖度时空分布特征及影响因素

典型矿区植被覆盖度时空分布特征及影响因素

Relationship embedding and environmental governance performance research of pollution in a mining area, China.

The aim of this study was to explore the enterprises in the mining area, in the face of environmental pollution, to use relationship embedding to acquire new key knowledge from the external network, and to improve environmental governance performance. In this paper, a model between relationship embedding and environmental governance performance was established, and five main hypotheses were proposed. Luliang Mountain Area is a typical mining area in China. And this study used 310 sample datum and regression analysis to empirically test the mechanism, taking Luliang Mountain Area as an example. First, SPSS statistical software was used for reliability and validity analysis of the questionnaire, and the results showed good. Then regression analysis was performed to test the hypothesis. The results showed that relationship embedding has a significant positive impact on environmental governance performance, and enterprises in the mining area use relationship embedding to obtain key knowledge, which can enhance environmental governance performance. Internal social capital has a positive adjustment effect on the relationship between relationship embedding and knowledge acquisition. In order to control environmental pollution in the mining area, enterprises should make full use of the relationship embedding, acquire new key knowledge, improve environmental governance capacity, and improve the environmental governance performance of enterprises.

Heavy Metal Pollution in Topsoil and Vegetables in the Typical Mining Area Near Gannan, Jiangxi Province, China

Abstract To provide a theoretical basis for soil management in mining areas, soil and vegetable samples were collected from the vegetable fields at a depth of 0–20 cm near the tungsten mining area ...

Comparative analysis of pore structure and fractal characteristics of micropores in medium and high rank coals——Taking the typical mining area of western Guizhou and eastern Yunnan as an example

In order to clarify the micropore pore structure characteristics of medium and high rank coal reservoirs, based on low temperature CO2 adsorption test and surface/volume fractal theory, the structure and fractal characteristics of medium and high coal rank micropores (0.40∼2nm) were analyzed. The results show that with the increase of coal metamorphism, the pore size of coal reservoirs changes from 0.55∼0.8nm to 0.5∼0.7nm, and the pore size is 0.5∼0.9nm. Microporous pores have good fractal characteristics, Dav1<Dav2 indicating stage the pore volume heterogeneity increases with the pore size in the pore range. Dav2 is positively correlated with the maximum vitrinite reflectance, indicating that the pore volume heterogeneity increases with the pore size in the micropore range. The heterogeneity of the surface area of the adsorption pore is far more complicated than the volume heterogeneity, Das1< Das2⩾Das3, indicating that the surface heterogeneity of the micropore decreases with the decrease of the pore size and tends to be stable; As the degree of metamorphism of coal increases. And the study shows that the influence of coal rank on surface heterogeneity decreases with the decrease of pore size.

Distribution and ecological risks of heavy metals in river sediments and overlying water in typical mining areas of China

The distribution and potential ecological risks of eight heavy metal elements including Cr, Cu, Zn, As, Cd, Pb, Hg, and W in the overlying water and sediments of the Taojiang River were investigated. The concentrations of eight heavy metals were measured by inductively coupled plasma mass spectrometer (ICP-MS), and the distribution coefficients were exploited to estimate the partition coefficient between overlying water and sediment phases, which were subsequently used to establish the potential ecological risk of heavy metals in sediments. The results revealed that the contents of Pb (33.47 μg·L−1), Cd (153.03 μg·L−1) and Hg (1.12 μg·L−1) in the water samples exceeded threshold values as proposed by the limits of the class III environmental quality standard. On the other hand, Cr, Cu, Zn, As, and Pb within sediments were below threshold limits.

Effects of environmental governance in mining areas: The trend of arsenic concentration in the environmental media of a typical mining area in 25 years

China has considered different environmental management measures (EMMs) in mining areas. However, their effects remain unclarified. In this study, the achievements and limitations of different EMMs of a typical mining area—Huangchang realgar mine—located in Hunan province were explored. The variations in the arsenic concentrations in the soil, agricultural products, drinking water, and atmosphere in 25 years of EMM implementation were investigated. Source control measures, such as ceasing mining and smelting activities, disposal of waste residues, and purifying wastewater, significantly reduced the arsenic concentrations in the atmosphere and surface water by more than 99%—from 68 μg m−3 and 0.42 mg L−1 to 3.63 ng m−3 and 4.31 μg L−1, respectively. The arsenic concentrations in agricultural products decreased by more than 78.8%—from 1.32 mg kg−1 in wheat to 0.28 mg kg−1 in vegetable and 0.13 mg kg−1 in maize—after the planting structure adjustment (PSA). However, the chronic daily intake of arsenic via product ingestion was 1.5 times higher than the benchmark dose lower confidence limit. Natural attenuation measures exerted limited effects on soil remediation; the arsenic concentration in the soil decreased insignificantly from 291.9 mg kg−1 to 213.3 mg kg−1. With the current attenuation rate, decreasing the soil arsenic concentration to under 30 mg kg−1 would require 47,900 years. The exceeding contaminant concentration in the resuspended dust, surface runoff, and agricultural products from the contaminated soil must be considered. China's EMMs in mining areas have achieved significant results, but the contaminated soil requires more attention and the PSA should accommodate the dietary habits and economic limits.

Experimental investigation of the wetting ability of surfactants to coals dust based on physical chemistry characteristics of the different coal samples

To select suitable surfactant as water-spray additive to improve dust suppression efficiency, six types of coal sample (lignite, long flame coal, non-caking coal, gas coal, coking coal, and anthracite) were selected from some typical mining areas in China, the influence of the physical chemistry characteristics of coal samples on the wetting ability of surfactants to the coals dust was investigated. Their proximate composition, ultimate content, chemical structure, surface morphology, pore structure parameters, and contact angle were determined. Three kinds of anionic surfactants – Sodium Alcohol Ether Sulphate (AES), Sodium Alpha-Olefin Sulfonate (AOS), Fatty Acid Methyl Esters Ethoxylate Sulfonate (FMES) – and one kind of nonionic surfactant – Coco Diethanolamide (CDEA) – were selected to carry out sedimentation experiments on the coal samples dust, to explore the main factors influencing the wettability of the coal samples dust. Among these factors, pore size is the main factor determining the wettability of coal dust, the contact angle decreases linearly (R2 = 0.96) with pore size increase. The experimental results demonstrate that the following factors produce correspondingly increased wettability: higher moisture content, lower carbon content, higher oxygen content, more oxygen-containing functional groups, and increased pore size. In addition, the wettability of the six types of the coal samples dust shows a high-low-high trend with metamorphic degree increase, lignite has the strongest wettability, and the coking coal with the highest degree of metamorphism in the selected bituminous coal sample has the weakest wettability. Moreover, compared with nonionic surfactants, anionic surfactants have stronger wetting ability, but the same anionic surfactants have different wetting abilities to coal dust with different metamorphic degrees. AOS has stronger wetting ability to the dust of long flame coal, non-caking coal, and anthracite; AES has stronger wetting ability to the dust of lignite and coking coal; and FMES has stronger wetting ability to the dust of gas coal. The research results provide a theoretical basis for different coal mines to select suitable surfactants as water-spray additives to improve dust suppression efficiency.

The Relationship Between Assistance Satisfaction and Negative Affect in Long-Term Social Assistance Recipients in China: The Moderating Role of Self-Acceptance.

Public welfare in China is less universal, comprehensive, and generous when compared with other welfare regimes, especially for individuals with occupational disease. The assistance satisfaction of Chinese pneumoconiosis patients, a typical group of long-term social assistance recipients, has been linked to diminished health and psychological well-being. Self-acceptance is theorized to promote well-being, which may buffer the negative consequences of negative emotion on assistance satisfaction. This research was conducted based on the survey data of 1,345 patients in typical mining areas of China. In addition to single-factor analysis of variance, descriptive analysis, and correlation analysis, a cluster analysis was performed to explore the profiles of participants' ratings of assistance satisfaction with five governing subjects: government, employing unit, medical institution, welfare organization, and laborer themselves. The results were as follows: (1) Social assistance satisfaction perceived by Chinese long-term social assistance recipients was at an average level, wherein self-assistance satisfaction perception was the lowest among five dimensions. (2) The overall perception of assistance satisfaction of Chinese long-term social assistance recipients was significantly correlated with educational background and household monthly income; specifically, the participants with higher levels of education and lower levels of income were more likely to have higher assistance satisfaction perception. (3) Cross analysis showed that participants with higher assistance satisfaction were mainly from the low-high group, having a lower level of negative affect, and higher level of self-acceptance. (4) The average negative affect level was above the scale midpoint (3.65) and negatively associated with each of the assistance satisfaction ratings. (5) The analysis yielded three distinct profiles—medium (19.26%), high (40%), and low (40.74%)—according to their degree of assistance satisfaction. Relative to the other profiles, low assistance satisfaction participants reported greater levels of negative affect in their daily life. However, self-acceptance moderated these effects, but no moderating effect was detected for individuals reporting greater levels of assistance satisfactory. Purpose is proved empirically a positive asset for promoting psychological adjustment in the period of receiving social assistance for Chinese long-term social assistance recipients.

Technical scheme and application of pressure-relief gas extraction in multi-coal seam mining region

A pressure relief gas extraction technical model of a typical mining area is proposed based on coal and gas simultaneous extraction theory. Flac3D was employed to model vertical stress and displacement contour plot characteristics of non-outburst coal seam (No. 4) on top of outburst coal seam (No. 2) along strike and incline directions. Field investigations were also conducted to verify the scientific nature of the simulation. The results demonstrate that gas pressure in No. 2 coal seam dropped to approximately 0.55 MPa in the pressure relief multi-coal seam. The highest expansion rate of the coal mine reached up to 2.58%. The pressure-relief angle was 76° along the incline direction and 60° along the strike direction. As the expansion rate and pressure-relief angle increased and the gas pressure decreased, a large amount of gas flowed into the gob of No. 4 from No. 2 coal seam and was later discharged through specific gas pipes, which eliminated No. 2 outburst risks. This study resulted in positive outcomes in that gas extraction time was reduced by 13.5 days, due to pressure relief, and drilling work load was reduced by 0.1161 m/t coal. This method ensures that gas is discharged from the outburst coal seam quickly and safely, demonstrating that the proposed technical model of pressure-relief gas extraction is effective in a multi-coal seam region.

煤矿复垦区土壤水动力学特性对下渗过程的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 煤矿复垦区土壤水动力学特性对下渗过程的影响 DOI: 10.5846/stxb201705020800 作者: 作者单位: 山西大学黄土高原研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划（2017YFC0505702） The influence of hydrodynamic characteristics on the infiltration process of soil water in a coal mine reclamation area Author: Affiliation: Institute of Loess Plateau,Shanxi University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:煤矿复垦区土壤水对植物生长、溶质运移以及土壤环境的变化起着至关重要的作用。定量揭示煤矿复垦区土壤水下渗过程是亟待诠释的关键科学问题。本研究通过测定典型矿区不同深度土壤非饱和导水率、容重、总孔隙度和粒径等水动力学参数，结合染色示踪试验，刻画矿区非饱和带土壤水运移过程。染色示踪结果显示30、60 L和90 L这3种实验下渗水量条件下，水流沿X方向侧向扩散的最大距离分别为10、30 cm和35 cm，沿Y方向侧向扩散的最大距离分别为10、25 cm和30 cm。互相关函数显示随着下渗水量增大，水流扩散作用也在加强，但过多水量并没有明显增加下渗深度和扩散距离。吸力大于300 hpa时，0.01-0.05 mm土壤粒径含量和非饱和导水率呈负相关关系；吸力和非饱和导水率采用指数函数拟合效果较好（r2>0.9），对拟合参数a、b和土壤容重（x）进行回归分析：a=0.0015x2-0.00499x+0.0004，b=0.0583x2+0.1234x-0.072。同一吸力下土壤容重大的土样非饱和导水率较小；吸力值为300 hpa是非饱和导水率的转折点；非饱和导水率和土壤容重呈现负相关关系，和总孔隙度呈现正相关关系，且二者的相关性随吸力的增加而降低。 Abstract:Soil water plays an important role in plant growth, solute transport, and soil environment changes. It is a key scientific problem to reveal the infiltration process of soil water in the unsaturated zone. This study used a typical mining area as the study area to investigate the unsaturated hydraulic conductivity, soil bulk density, porosity, and particle size in the different depths of soil layer by conducting a dye tracer experiment. This study aimed to elucidate the infiltration process of soil water and distribution characteristics in the unsaturated zone. The results showed that, at the experimental infiltration water of 30, 60, and 90 L, the greatest diffusion distance are 10, 30, and 35 cm, respectively, along the X direction and 10, 25, and 30 cm, respectively, along the Y direction. Soil water infiltration showed obvious heterogeneity and spatial variability. With more amount of water, it infiltration deeper and diffusion wider, and this was noted in a declining trend. When suction was greater than 300 hpa, the content of soil particle size between 0.01 and 0.05 mm was negatively correlated with unsaturated hydraulic conductivity. Unsaturated hydraulic conductivity decreased nonlinearly with increase in suction, suction and unsaturated hydraulic conductivity fitting with the exponential function (r2 > 0.9), and regression analysis was performed for the parameters a, b, and soil bulk density (x) as follows:a=0.0015x2 - 0.00499x + 0.0004, b=0.0583x2 + 0.1234x - 0.0726. Under the same suction, bulk density of soil was greater, whereas unsaturated hydraulic conductivity was smaller. when the suction value is 300 hpa, the unsaturated hydraulic conductivity reaches a peak value. Unsaturated hydraulic conductivity was negatively correlated with bulk density, whereas positively correlated with total porosity, and the correlation rate decreased with increasing suction. 参考文献 相似文献 引证文献

Health Risk Assessment of Trace Metals in Various Environmental Media, Crops and Human Hair from a Mining Affected Area.

Long term exposure to trace metals in various media is of great concern for people living in known pollution sources, such as mining and industrial activities. Health risk assessment and human hair analysis can provide important information for local environmental management. Information on distribution characteristics of trace metals in soil, water, sediment, air, local crops, and human hair from a typical mining area in southern China was collected. Results show there exists severely trace metal contamination in soil, sediment, and air. Arsenic and Pb contents in the local children’s hair are higher than the upper reference values, and the accumulation of residents’ hair trace metals shows great correlation with the ingestion and inhalation pathways. Arsenic contributes 52.27% and 58.51% to the total non-cancer risk of adults and children, respectively. The cancer risk of Cd in adults and children are 4.66 and 3.22 times higher than the safe level, respectively. Ingestion exposure pathway of trace metals largely contributes to the total non-cancer and cancer effect. The metals As, Cd, and Pb are major risk sources and pollutants that should be given priority for management, and ingestion pathway exposure to trace metals through soil and crops should be controlled.